<template>
  <div class="slide-show" @mouseover="clearInv" @mouseout="runInv">
    <template v-if="slides.length">
      <div class="slide-img">
        <a :href="slides[nowIndex].href">
          <transition :name="transitionName + '-slide-trans'">
            <img v-if="isShow" :src="slides[nowIndex].src">
          </transition>
          <transition :name="transitionName + '-slide-trans-old'">
            <img v-if="!isShow" :src="slides[nowIndex].src">
          </transition>
        </a>
      </div>
      <h2>{{ slides[nowIndex].title }}</h2>
      <ul class="slide-pages">
        <li @click="goto(prevIndex)">&lt;</li>
        <li v-for="(item, index) in slides" @click="goto(index)">
          <a :class="{on: index === nowIndex}">{{ index + 1 }}</a>
        </li>
        <li @click="goto(nextIndex)">&gt;</li>
      </ul>
    </template>
    <template v-else>
      <div>没有图片</div>
    </template>
  </div>
</template>

<script>
export default {
  props: {
    slides: {
      type: Array,
      default: function () {
        return [];
      }
    },
    inv: {
      type: Number,
      default: 1000
    }
  },
  data () {
    return {
      transitionName: 'left',
      nowIndex: 0,
      isShow: true
    };
  },
  computed: {
    prevIndex () {
      this.transitionName = 'right';
      if (this.nowIndex === 0) {
        return this.slides.length - 1;
      } else {
        return this.nowIndex - 1;
      }
    },
    nextIndex () {
      this.transitionName = 'left';
      if (this.nowIndex === this.slides.length - 1) {
        return 0;
      } else {
        return this.nowIndex + 1;
      }
    }
  },
  methods: {
    goto (index) {
      this.isShow = false;
      setTimeout(() => {
        this.isShow = true;
        this.nowIndex = index;
      }, 10);
    },
    runInv () {
      this.invId = setInterval(() => {
        this.transitionName = 'left';
        this.goto(this.nextIndex);
      }, this.inv);
    },
    clearInv () {
      clearInterval(this.invId);
    }
  },
  mounted () {
    this.runInv();
  }
};
</script>

<style scoped>
  .left-slide-trans-enter-active {
    transition: all .5s;
  }
  .left-slide-trans-enter {
    transform: translateX(900px);
  }
  .left-slide-trans-old-leave-active {
    transition: all .5s;
    transform: translateX(-900px);
  }

  .right-slide-trans-enter-active {
    transition: all .5s;
  }
  .right-slide-trans-enter {
    transform: translateX(-900px);
  }
  .right-slide-trans-old-leave-active {
    transition: all .5s;
    transform: translateX(900px);
  }

  .slide-show {
    position: relative;
    margin: 15px 15px 15px 0;
    width: 900px;
    height: 500px;
    overflow: hidden;
  }
  .slide-show h2 {
    position: absolute;
    left: 0;
    bottom: 0;
    box-sizing: border-box;
    width: 100%;
    height: 30px;
    padding-left: 15px;
    text-align: left;
    line-height: 30px;
    color: #fff;
    background: #000;
    opacity: .5;
  }
  .slide-img {
    width: 100%;
  }
  .slide-img img {
    width: 100%;
    position: absolute;
    top: 0;
    left: 0;
  }
  .slide-pages {
    position: absolute;
    bottom: 10px;
    right: 15px;
  }
  .slide-pages li {
    display: inline-block;
    padding: 0 10px;
    cursor: pointer;
    color: #fff;
  }
  .slide-pages li .on {
    text-decoration: underline;
    color: red;
  }
  .slide-pages li a {
    color: #fff;
  }

  .slide-pages{
    -webkit-user-select: none;
  }
</style>
